Vacuum pick up head

ABSTRACT

An improved pick-up assembly for use in moving articles includes a pick-up head having an array of suckers for applying suction to articles to be moved. A control apparatus is provided for controlling a flow of fluid through passages extending from a source of low pressure to the suckers so that only the suckers which are adjacent to the surface of an article to be moved are maintained in a fluid communication with the source of low pressure. This control apparatus includes a plurality of solenoid operated valves each of which is associated with one of the passages. An actuator circuit effects initial operation of the solenoids to open the valves for a short period of time. If a sucker applies suction to the surface of an article to be moved during this short period of time, a holding circuit is completed to prevent subsequent closing of the valve associated with the sucker. However, the valves associated with suckers which are ineffective to apply suction to the article to be moved are closed at the end of the short period of time. An indicator circuit is associated with each of the holding circuits to provide an indication of which of the suckers are effective to apply suction to an article to be moved.

United States Patent Nielson et al.

[541 VACUUM PICK UP HEAD Jay P. Nielsen, Bountiful; G. Allen Allred, Salt Lake City, both of Utah [72] Inventors:

[73] Assignee: Eaton Yale & Towne lnc., Cleveland, Ohio 221 Filed: April 15, 1971 211 Appl.No.: 134,208

521 mu. ..294/6s,214/6 FS 511 Int. Cl. ..B66c 1/02 581 Field 61 Search....294/64 R, 65; 214/6 FS, 1 BS, 214/85 D, 650 so; 248/362, 363

[56] References Cited UNITED STATES PATENTS 3,476,632 11/1969 Comeliusm. ..'..l5 6/366 3,598,439 8/1971 Dahlquist etal ....294/65 Primary Examiner-Evon C. Blunk AssistantExaminer-Johnny D. Cherry Attorney-Yount and Tarolli 3,697,1 12 Oct. 10, 1972 ABSTRACT An improved pick-up assembly for use in moving articles includes a pick-up head having an array of suckers for applying suction to articles to be moved. A control apparatus is provided for controlling a flow of fluid through passages extending from a source of low pressure to the suckers so that only the suckers which are adjacent to the surface of an article to be moved are maintained in a fluid communication with the source of low pressure. This control apparatus includes a plurality of solenoid operated valves each of which is associated with one of the passages. An actuator circuit efiects initial operation of the solenoids to open the valves for a short period of time. If a sucker applies suction to the surface of an article to be moved during this short period of time, a holding circuit is completed to prevent subsequent closing of the valve associated with the sucker. However, the valves associated with suckerswhich are ineffective to apply suction to the article to be moved are closed at the end of the short period of time. An indicator circuit is associated with each of the holding circuits to provide an indication of which of the suckers are effective to apply suction to an article to be moved.

18 Claims, 8 Drawing Figures PATENTEiibbI 10 I972 SHEET 2 0F 2 G ALLEN fill/QED ATTORNEYS V VACUUM PICK UP HEAD This invention relates to an article handling apparatus and more particularly to an improved pick-up assembly which grips an article by applying suction to the article.

A known article handling system includes a stacker crane having a carrier or pick-up head for gripping containers or other articles to be moved by the stacker crane. The pick-up head has a plurality of suckers or vacuum cups which engage and apply suction to the articles to thereby grip the articles. If some of these suckers are located in an area where there are no articles to be engaged by the suckers or at cracks between adjacent articles, these suckers should be deactivated to prevent the operating efficiency of the lift head from being impaired by an excessive flow of air to a source of suction or low pressure. In addition, if only selected articles are to be removed from a matrix of articles, the suckers adjacent to articles which are not to be moved must be deactivated.

Accordingly, it is an object of this invention to provide a new and improved pick-up head having suckers which are deactivated if they are located so as to be ineffective to apply suction to an article to be moved.

Another object-of this invention is to provide a newand improved pick-up head having a plurality of electrically operated actuators for opening valves to activate a plurality of suckers and a plurality of holding circuits for preventing a subsequent closing of the valves associated with suckers which are effective to grip the article to be moved.

Another object of this invention is to provide a new and improved pick-up head having suckers which are automatically deactivated if they are locatedsoas 'to be ineffective to apply suction to an article to be moved and an indicator assembly for indicating which of the suckers are effective to apply suction to the article.

Another object of this invention is to provide a new and improved pick-up assembly for use in moving articles and including a control means for controlling fluid flow through passages connecting fluid inlets in a pickup head with a source of low pressure or suction so that only the fluid inlets which are adjacent to the surface of an article to be moved are maintained in fluid communication with the source of low pressure, and wherein the control means includes a plurality of electrical actuators each of which is operable to open an associated valve for a short period of time to thereby connect an associated inlet in the pick-up head with the source of low pressure so that suction is applied to the surface of an article to be moved by the adjacent fluid inlets at the end of the short period of time, a plurality of retaining means prevent closing of the valves which are associated with inlets at which suction is applied to an article to be moved.

Another object of this invention is to provide a new and improved pick-up assembly in accordance with the next preceding object and wherein the retaining means includes holding circuits for maintaining associated electrical actuators operated at the end of the short period of time in response to the application of suction to an article at the fluid inlets associated with the electrical actuators.

Another object of this invention is to provide a new and improved pick-up assembly for use in moving articles wherein the pick-up assembly includes a pick-up head having an operating side with an array of fluid inlets, a control means is provided to control fluid flow through passages extending from the fluid inlets to a source of low pressure so that only fluid inlets which are adjacent to the surface of an article to be moved are connected in fluid communication with the source of low pressure while the article is moved by the pick-up assembly, and wherein an indicator means is provided for indicating which of the fluid inlets are connected to the source of low pressure as the article is moved by the pick-up assembly.

These and other objects and features of the present invention will become more apparent upon a consideration of the following description taken in connection with the accompanying drawings wherein:

FIG. 1 is a fragmentary schematic illustration of one of several possible configurations of an article handling apparatus having a pick-up head constructed in accordance with the present invention;

FIG. 2 is a partially broken-away plan view illustrating the construction of a control assembly mounted in the pick-up head of the article handling apparatus of FIG. 1 to control the application of suction to an article by an associated sucker or vacuum cup on an operating side of the pick-up head;

FIG. 3 is a sectional view, taken generally along the line 3-3 of FIG. 2, illustrating the relationship between a valve for controlling the application of suction by an associated sucker and a solenoid for opening and closing the valve;

FIG. 4 is a sectional view, taken generally along the line 4-4 of FIG. 2, illustrating the construction of a retaining assembly which, in response to the application of suction to an article by an associated sucker, prevents the solenoid of FIG. 3 from closing the associated valve;

FIG. 5 is a sectional view illustrating the relationship between the solenoid and valve of FIG. 3 when the valve is open and suction is being applied to an article;

FIG. 6 is a sectional view, generally similar to FIG. 4, illustrating the retaining assembly in an operated condition in which it is effective to prevent closing of the associated valve;

FIG. 7 is a schematic illustration of electrical circuitry associated with the control assembly of FIGS. 2-6; and

F168 is a schematic illustration of a display panel for indicating which of the suckers on the pick-up head are effective to apply suction to an article.

Although a pick-up head 10 constructed in accordance with the present invention can be used in many different types of assemblies for moving articles, the pick-up head is illustrated in FIG. 1 in association with a stacker crane 12. The stacker crane is used to deposit articles or containers 14 at various locations in bins 16 and to retrieve the articles from the bins. The pick-up head 10 includes a plurality of flexible suckers or vacuum cups 20 which are disposed in a rectangular array on an operating or face side 22 of the pick-up head 10.

When the pick-up head 10 is to be utilized to transfer one of the containers 14, for example the container 14a, either to or from a support pallet or base 26, the pick-up head 10 is moved downwardly by a drive arrangement 28. This downward movement causes the resilient suckers 20 to sealingly engage an upper surface 30 of the container 14a. The suckers which are adjacent to the upper surface 30 of the container 14a are then connected with a source of low pressure or suction so that suction is applied to the container and it is firmly gripped in a known manner.

After the suckers 20 have firmly gripped the container 14a, the pick-up head is moved by the stacker crane 12 to a bin 16 where the container is to be deposited. The application of suction to the upper surface 30 of the container 14a is then terminated so that the container is released in the selected bin 16. Of course, if a container was to be transferred from a bin 16 to the support pallet or base 26, the pick-up head 10 would grip the container in the bin and move it to a position overlying the base or pallet. The application of suction to the container would then be terminated so that it would drop downwardly onto the pallet.

It is contemplated that the pick-up head 10 will be used to grip and move a plurality of articles or containers 14 simultaneously. Accordingly, the operating side 22 of the pick-up head 10 has a surface area which is greater than the surface area of any one of the containers 14. This enables the rectangular array of suckers to be large enough to extend over the upper surfaces of a plurality of containers and to grip the plurality of containers as they are moved by the stacker crane 12. However, if one of the suckers 20 is disposed across a crack between a pair of containers gripped by the pick-up head 10, the sucker may be ineffective to sealingly engage either of the containers so that air can flow through the crack between the containers to the sucker. In a known article handling system this air will then flow from the sucker to a vacuum pump or other source of low pressure (not shown) at a relatively high rate and will impair the ability of the vacuum pump to provide the necessary suction at the suckers 20. Of course, if only a single container is gripped by the pickup head 10, such as the container 14a, the suckers 20 which do not sealingly engage the container will be exposed to the atmosphere. Therefore, if these suckers were connected in fluid communication with the vacuum pump, its ability to reduce the pressure at the suction cups which are in sealing engagement with the container 14a would be impaired.

In accordance with a feature of the present invention, a plurality of control assemblies 34 (FIGS. 2-6) are mounted in the pick-up head 10 in association with the suckers 20. Each of the control assemblies 34 is operable to control the application of suction by an associated one of the suckers 20.

When only a single container, such as the container 140, is to be gripped and moved away from a group of containers, the control assemblies 34 are selectively operated to activate only the suckers 20 disposed next to the upper surface of the selected container 14a. In addition, if a sucker 20 is disposed over a crack or is otherwise ineffective to apply suction to a container when one or more containers are to be moved, the ineffective sucker is rendered inactive by the associated control assembly 34. Each of the control assemblies 34 includes a passage 38 formed in a housing 39. The passage 38 has an inlet 40 (see FIG. 3) at an associated sucker 20 and an outlet 42 to a chamber 44 in the pickup head 10. The chamber 44 is connected with a vacuum pump so that there is a relatively low fluid pressure in the chamber. Fluid flow through the passage 38 is controlled by a valve 48. When the valve '48 is closed, a valve ball 49 engages a valve seat 50 (see FIGS. 2 and 3) to block fluid flow from the sucker 20 through the passage 38 to the low pressure chamber 44.

When an article is to be gripped by the suction cup 20, an electrical actuator 52 in the associated control assembly 34 is operated to move the valve ball 49 from the closed position of FIGS. 2 and 3 to the open position of FIG. 5. The electrical actuator 52 includes a solenoid 54 having a plunger 56 which is moved from the retracted position of FIG. 5 to push the valve member 49 away from the valve seat 50 against the influence of abiasing spring 60 to thereby connect the inlet 40 in fluid communication with the relatively low fluid pressure in the chamber 44. Air is then drawn from a chamber 62 (FIG. 5), formed between the sucker 20 and the upper surface 30 of the container 14a, through the passage 38 to the low pressure chamber 44. Of course, this results in the application of suction to the container 14a so that the sucker 20 firmly grips the container.

If the suction cup 20 of FIGS. 3 and 5 is not in engagement with an article to be moved, the solenoid 54 is de-energized after the valve 48 has been open for only a very short time. De-energization of the solenoid 54 retracts the plunger 56 and the spring 60 moves the valve member 49 into firm sealing engagement with the valve seat 50. Once the valve ball 49 has moved to the closed position, the relatively high air pressure in the passage 38 presses the ball against the valve seat 50 since the opposite side of the ball is exposed to the relatively low fluid pressure in the chamber 44.

From the foregoing, it is apparent that the low pressure chamber 44 is connected in fluid communication with the sucker 20 for a relatively short period of time when the sucker is not located so as to sealingly engage an article to be moved. In fact, if it is known that certain of the suckers 20 in the lift head 10 will not be disposed adjacent to an article to be moved, the solenoids 54 in the control assemblies 34 associated with these suckers need not be energized to open the associated valves 48. Of course, this will tend to minimize the operating load on the vacuum pump which is connected to the low pressure chamber 44.

Although the valves 48 associated with the suckers which do not engage an article are advantageously closed by de-energizing the associated solenoids 54, the valves 48 in the control assemblies 34 associated with suckers 20 which engage an article must be retained in the opened condition if the suckers are to effectively grip the article. Accordingly, a retaining or latching device 64 is associated with the solenoid 54 and valve 48 in each of the control assemblies 34 to retain the valves in the open condition when the associated suckers 20 are effective to apply vacuum to a surface of an article to be moved. Since the valve 48 should only remain open when the associated sucker is effective to apply suction to an article to be moved, the holding device 64 is operated from the release condition of FIGS. 2 and 4 to the actuated or holding condition of FIG. 6 in response to the application of suction to an article to be moved.

When the holding device 64 is in the actuatedcondition of FIG. 6, a switch 68 is closed to complete a holding circuit (see FIG. 7) for the associated solenoid 54. The switch 68 is operated from the open condition of FIGS. 2 and 4 to the closed condition of FIG. 6 by a cylindrical plunger 72. The plunger 72 is moved toward the left (as viewed in FIGS. 2 and 4) in a chamber 74 in response to the application of suction to an article to be gripped by the associated sucker 20. The leftward movement of the plunger or cylinder 72 in the chamber 74 depresses an actuator button 78 on the switch 68 (see FIG. 6) to close the switch 68 and complete-a holding circuit for the associated solenoid 54.

The plunger 72 is moved in the chamber 74 to actuate the switch 68 against the bias of the spring loaded actuator button 78 in response to the application of suction to an article to be moved by the associated sucker and the resulting decrease in pressure in the passage 38. This is accomplished by exposing a head end 86 of the plunger 72 to the relatively low pressure in the passage 38 and exposing a tail end 88- of the plunger to atmospheric pressure through apassage 90 (FIG. 6). The resulting pressure differential across the plunger 72 moves it toward the switch 68 to operate the spring biased actuator button 78.

Accordingly, when the valve 48 is opened-(see FIG. 5), air is drawn from the inlet 40 through the passage 38 to the low pressure chamber 44. If the annular lower lip 92 of the sucker 20 is in sealing engagement with an article to be moved, air is drawn from the chamber 62 between the sucker 20 and the article, through the passage 38 and outlet 42 to the chamber 44. This results in the pressure in the chamber 64 and passage 38 being reduced. The reduction of the pressure in the passage 38 is communicated to the chamber 74 by an arm 94 of the passage 38 (see FIG. 2). Therefore, the head end 86 of the plunger 72 is exposed in a relatively low pressure in the passage 38.

Since the passage 90 (FIG. 6) connects the opposite end of the chamber 74 in fluid communication with air at atmospheric pressure, the tail end 88 of the plunger 72 is exposed to fluid pressure which is higher than the fluid pressure in the passage 38. Therefore, the relatively high fluid pressure against the tail end 88 of the plunger 72 presses the plunger toward the left (as viewed in FIGS. 4 and 6) to depress the actuator button 78 against the influence of an internal biasing spring. The tail end 88 of the plunger 72 is advantageously provided with a stop section 96 which engages an end surface 98 of the chamber 74 when the plunger is in the released position of FIGS. 2 and 4. This ensures that the pressure in the passageway 90 is communicated to the tail end 88 of the plunger 72. Although the plunger 72 has been illustrated as being biased to the right (as viewed in FIGS. 4 and 6) by the switch actuator 78, it should be understood that a separate biasing spring could be provided to urge the plunger to the released condition of FIG. 4.

Although only a single control assembly 34 has been shown in association with one of the suckers 20 in FIGS. 3 and 5, it should be understood that a separate control assembly 34 is associated with each of the suckers 20 (FIG. 1). Each of the control assemblies 34 is provided with its own circuitry 100. The control circuitry 100 includes threeinterconnectedcircuits. One

of these is an actuator circuit 102 for initially energizing the solenoid 54 for a short time. A latch or holding circuit 104 of the holding device 64 retains the solenoid 54 in the energized condition upon a closing of the switch 68 by the plunger 72 in response to the application of suction to an article to be moved. Finally, an indicator circuit 106 is provided to indicate when the valve 48 is open and suction is being applied to an article.

When an article, such as the container 14a, is to be moved by the pick-up head 10, a switch 110 in the actuator circuit 102 is closed to activate an oscillator 112. The oscillator 112 is of the one-shot monostable type and upon closure of the switch 110 provides an output pulse P1 of a predetermined duration. The output pulse P1 energizes the solenoid 54 for a relatively short period of time, that is a period of time which is equal to the duration of the pulse P1.

This brief energization of the solenoid 54 causes the plunger 56 to be extended to move the valve ball 49 to the open position of FIG. 5 against the influence of the biasing spring 60. If the sucker 20 is exposed to the atmosphere, that is if the sucker is spaced from the containers 14 or other articles to be moved, the pressure in the passage 38 will remain at substantially atmospheric pressure. However, if the sucker 20 is in sealing engagement with a container (as shown in FIG. 5), opening of the valve 48 for even a brief period of time will result in the pressure in the passage 38 being reduced and the plunger 72 being moved to close the switch 68 under the influence of the pressure differential across the plunger. Closing the switch 68 completes the holding or retaining circuit 104 to a suitable D.C. source to maintain the solenoid 54 energized at the end of the relatively short time period during which the solenoid is energized by the pulse P1.

Under certain circumstances, it is contemplated that the pick-up head will be utilized to engage only a predetermined article in a matrix or group of articles. When this is to be done, the pick-up head 10 is positioned over the group of articles and only the suckers 20 over the selected article are activated. The other suckers remain inactive since they are over articles which are not to be moved. To accomplish this, only the switches 110 associated with the suckers 20 over the article to be moved are closed. The switches 1 10 associated with suckers which are over articles which are not to be moved remain open so that the solenoids 54 associated with these suckers are not energized.

Assuming that the control circuitry of FIG. 7 is associated with the sucker 20 which is in engagement with an article to be moved, such as the container 14a, the switch 68 in the latching retaining circuit 104 is closed by the plunger 72 in the manner previously explained. Closing the switch 68 completes a holding circuit through a diode 116 from a source of D.C. current to a ground line 118 to maintain the solenoid 54 energized and the associated valve 48 open. Therefore, the chamber 62 in the associated sucker 20 continues to be connected in fluid communication with the low pressure chamber 44 in the pick-up head 10 after the pulse Pl has ended to thereby provide for the application of suction to the container 14a.

After the stacker 12 has been operated to move the container 14a to a position where it is to be deposited, a

release switch 120 in the holding circuit 104 is opened to interrupt the flow of current energizing the solenoid 54. This results in the valve 48 being closed by the biasing spring 60. The porosity of the container 14a and leakage around the vacuum cup 20 is sufficient to allow the pressure within the chamber 62 and passage 38 to be restored so that the sucker 20 releases the container. If the suckers 20 are utilized to move containers which are relatively leak-free, it is contemplated that a second valve will be opened upon de-energization of the solenoid S4 to vent or exhaust the chamber 62 and passage 38 to the atmosphere. However, with most containers the leakage is sufficient to result in the release of the container by the sucker 20 upon a closing of the valve 48.

When the pick-up head is to be used to move one or more containers, the number of containers gripped by the pick-up head and their pattern on the pick-up head is shown on a display panel 130. The display panel 130 includes a plurality of lamps or lights 134 which form a part of the sensor circuits 106 associated with control assemblies 34 for each of the suckers 20. A lamp 134 and a control circuit associated with one of the suckers is lit or energized upon a closing of the holding switch 68 associated with that sucker. Thus, closing the switch 68 (see FIG. 7) connects the lamp 134 in the indicator circuit 106 with the source of DC. current for energizing the solenoid 54.

The lamps 134 on the display panel 130 are arranged in an array having a configuration which is the same as that of the array of suckers 20 on the pick-up head 10. Of course, the number and arrangement of suckers 20 on the pick-up head 10 can be varied in accordance with the environment in which the pick-up head is to be used. Therefore, when a particular one of the suckers 20 is activated to grip a container, such as the container 14a, the indicator light 134 associated with the sucker is lit on the display panel 130. Since the indicator lights 134 are arranged in the same spatial relationship as are the suckers 20, the pattern of energized lights 134 on the display panel 130 indicates the arrangement and number of containers gripped by the pick-up head 10.

[t is contemplated that the display panel 130 will be particularly useful in environments where an operator for the pick-up head 10 is at a location which is remote from the location where the pick-up head is utilized to move containers. Since selected suckers 20 on the pick-up head 10 can be activated by closing the switches 110 in the associated actuator circuits 102, the pick-up head 10 can be utilized to grip a selected container in a group of containers. An operator at a remote location can determine whether or not only the selected container has been gripped by 1 merely checking the pattern of the illuminated lights 134 on the display panel 130.

In view of the foregoing description, it can be seen that the pick-up head 10 can be utilized to pick up different numbers of articles having different dimensions. For example, when a specific article, such as the container 14a, is to be selected from a group of articles, only the suckers which are adjacent to the upper surface 30 of the container 14a are activated to apply suction to the container. The other suckers 20 which are not in engagement with the container to be moved are maintained inactive so that they are ineffective to apply suction to the articles which are not to be moved. To enable this to be accomplished, a control assembly 34 is provided within the pick-up head 10 in association with each of the suckers 20. The control assemblies 34 control the flow of fluid through the passages 38 associated with the suckers 20 so that only the suckers 20 which are adjacent to the surface of an article to be moved are connected in fluid communication with the low pressure chamber 44 while the article is being moved by the pick-up head 10.

Each of the control assemblies 34 includes a valve 48 which is opened and closed by operation of an associated solenoid 54. When a sucker is to grip an article to be moved, an actuator circuit 102 energizes the associated solenoid 54 for a short, predetermined period of time to open the valve 48 associated with the sucker 20. Upon an opening of the valve 48, a switch 68 in the associated retaining or holding circuit 104 is closed by the plunger 72 in response to the reduction in fluid pressure in the passage 38. Once the switch 68 is closed, the associated sucker maintains a firm grip on the article to be moved until a release switch is opened to interrupt or break the holding circuit 104. An indicator lamp 134 is advantageously associated with the holding circuit 104 to provide an indication on a display panel that the associated sucker has been activated to apply suction to the article being moved.

Having described specific preferred embodiments of the invention, the following is claimed:

1. A pick-up assembly for use in moving articles, said pick-up assembly comprising a pick-up head, sucker means on said pick-up head for engaging an article and applying suction to the article, valve means operable between an open condition in which said sucker means is connected with a source of low pressure and a closed condition, electrical actuator means for operating said valve means from said closed condition to said open condition, main circuit means for activating said electrical actuator means to said open condition, and holding circuit means for preventing deactivation of said electrical actuator means and operation of said valve means from said open condition to said closed condition in response to the application of suction to an article by said sucker means.

2. A pick-up assembly as set forth in claim 1 further including indicator means for indicating when said valve means is in the open condition and said sucker means is effective to apply suction to an article.

3. A pick-up assembly as set forth in claim 1 wherein said holding circuit means includes a switch and means for actuating said switch in response to the application of suction to an article by said sucker means.

4. A pick-up assembly as set forth in claim 1 wherein said sucker means includes a plurality of suckers arranged in an array on said pick-up head, said valve means includes a plurality of valves each of which is associated with one of said suckers, and said electrical actuator means includes a plurality of solenoids each of which is associated with one of said valves.

5. A pick-up assembly for use in moving articles, said pick-up assembly comprising a pick-up head having an array of fluid inlets on an operating side of the pick-up head, a plurality of passages each of which extends from an associated one of said fluid inlets to a source of low pressure, and control means for controlling fluid flow through said passages so that only the fluid inlets which are adjacent to the surface of an article to be moved are connected in fluid communication with the source of low pressure while the article is moved by the pick-up assembly, said control means including a plurality of valves each of which is associated with one of said passages and is operable between a closed condition blocking fluid flow through the associated passage and an open condition, a plurality of electrical actuators each of which is associated with one of said valves to effect operation of the associated valve between the closed and open conditions, electrical circuit means for effecting operation of at least some of said plurality of actuators for a predetermined period of time to operate at least some of said plurality of valves ,to the open condition to thereby connect at least some of the fluid inlets on the operating side of said pick-up head with the source of low pressure for a predetermined period of time to enable the fluid inlets adjacent to the surface of an article to apply suction to the surface of the article, said circuit means being operable at the end of the predetermined period of time to effect a closing of any of said valves which are associated with fluid inlets other'than fluid inlets through which suction is being applied to an article by effecting operation of the actuators associated withthese valves, and a plurality of retaining means each of which is associated with one of said valves for preventing operation of the one valve to the closed condition at the end of the predetermined time period when suction is applied during the predetermined time period to a surface of an article at the fluid inlet associated with the one valve.

6. A pick-up assembly as set forth in claim 5 wherein each of said actuators includes solenoid means for operating the associated one of said valves between the open and closed conditions and each of said retaining means includes a holding circuit means for preventing the associated solenoid means from being operated and a closing of the associated valve at the end of the predetermined time period when suction is applied to the surface of an article to be moved at the associated fluid inlet.

7. A pick-up assembly as set forth in claim 6 further including a plurality of indicator means each of which is electrically connected with an associated holding circuit means and is operable to indicate when the associated one of said valves is in the open condition at the end of the predetermined period of time.

8. A pick-up assembly as set forth in claim 5 wherein each of said retaining means includes an electrical switch which is electrically connected with the associated one of said actuators and is operable from a first condition to a second condition to prevent operation of the associated actuator and the associated one of said valves from the open condition to the closed condition at the end of the predetermined time period, each of said retaining means further including means for operating said electrical switch to the second condition in response to the application of suction to a surface of an article in the associated fluid inlet.

9. A pick-up assembly as set forth in claim 8 further including display means for indicating which of said valves are in the open condition at the end ofthe predetermined time period and the spatial relationship between the fluid inlets associated with these valves.

10. A pick-up assembly as set forth in claim 5 wherein each of said retaining means includes means for defining a chamber which is connected in fluid communication with the source of low pressure upon operation of the associated one of said valves to the open condition and means which is movable in response to a change in pressure to prevent operation of the associated one of said valves to the closed condition.

1 l. A pick-up assembly as set forth in claim 5 further including a plurality of flexible cups each of which is mounted on said pick-up head in association with one of said fluid inlets and is operable to sealingly engage a surface of an article to be moved to facilitate the application of suction to the surface of the article.

12. A pick-up assembly as set forth in claim 5 further including means for indicating which of said valves is in the open condition at the end of the predetermined time period.

13. A pick-up assembly for use in moving articles, said pick-up assembly comprising a pick-up head having an array of fluid inlets, a plurality of passages each of which extends from an associated one of said fluid inlets to a source of low pressure, control means for controlling fluid flow through said passages so that only fluid inlets which are adjacent to the surface of an article to be moved are connected in fluid communication with the source of low pressure while the article is moved by the pick-up assembly, and indicator means for indicating which of the fluid inlets are connected to the source of low pressure as the article is moved by the pick-up assembly.

14. A pick-up assembly as set forth in claim 13 wherein said indicator means includes display means for indicating the spatial relationship between the fluid inlets which are connected to the source of low pressure as the article is moved by the pick-up assembly.

15. A pick-up assembly as set forth in claim 14 wherein said display means includes a plurality of lights which are arranged in an array similar to the array of fluid inlets, said indicator means further including a plurality of switches each associated with one of said fluid inlets, means for operating each of said switches from a first condition to a second condition when the associated one of said fluid inlets is connected to the source of low pressure as the article is moved by the pick-up assembly, and circuit means for electrically connecting each of said switches to an associated one of said lights.

16. A pick-up assembly as ,set forth in claim 13 wherein said indicator means includes a plurality of switches each of which is associated with one of said fluid inlets and is operated from a first condition to a second condition upon application of suction to the surface of an article at the associated fluid inlet, said control means including a plurality of valves each of which is associated with one of said passages and is operable between a closed condition blocking fluid flow through the associated passage and an open condition, a plurality of electrical actuators each of which is associated with one of said valves for operating the associated valve to the open condition, and circuit means for activating said electrical actuators upon closing of the associated one of said switches.

low pressure, said display means including a plurality of lights arranged in an array similar to the array of fluid inlets, said indicator means further including circuit means interconnecting said switches and said lights to effect energization of a light associated with one of said switches when the associated switch is in the second condition. 

1. A pick-up assembly for use in moving articles, said pick-up assembly comprising a pick-up head, sucker means on said pick-up head for engaging an article and applying suction to the article, valve means operable between an open condition in which said sucker means is connected with a source of low pressure and a closed condition, electrical actuator means for operating said valve means from said closed condition to said open condition, main circuit means for activating said electrical actuator means to said open condition, and holding circuit means for preventing deactivation of said electrical actuator means and operation of said valve means from said open condition to said closed condition in response to the application of suction to an article by said sucker means.
 2. A pick-up assembly as set forth in claim 1 further including indicator means for indicating when said valve means is in the open condition and said sucker means is effective to apply suction to an article.
 3. A pick-up assembly as set forth in claim 1 wherein said holding circuit means includes a switch and means for actuating said switch in response to the application of suction to an article by said sucker means.
 4. A pick-up assembly as set forth in claim 1 wherein said sucker means includes a plurality of suckers arranged in an array on said pick-up head, said valve means includes a plurality of valves each of which is associated with one of said suckers, and said electrical actuator means includes a plurality of solenoids each of which is associated with one of said valves.
 5. A pick-up assembly for use in moving articles, said pick-up assembly comprising a pick-up head having an array of fluid inlets on an operating side of the pick-up head, a plurality of passages each of which extends from an associated one of said fluid inlets to a source of low pressure, and control means for controlling fluid flow through said passages so that only the fluid inlets which are adjacent to the surface of an article to be moved are connected in fluid communication with the source of low pressure while the article is moved by the pick-up assembly, said control means including a plurality of valves each of which is associated with one of said passages and is operable between a closed condition blocking fluid flow through the associated passage and an open condition, a plurality of electrical actuators each of which is associated with one of said valves to effect operation of the associated valve between the closed and open conditions, electrical circuit means for effecting operation of at least some of said plurality of actuators for a predetermined period of time to operate at least some of said plurality of valves to the open condition to thereby connect at least some of the fluid inlets on the operating side of said pick-up head with the source of low pressure for a predetermined period of time to enable the fluid inlets adjacent to the surface of an article to apply suction to the surface of the article, said circuit means being operable at the end of the predetermined period of time to effect a closing of any of said valves which are associated with fluid inlets other than fluid inlets through which suction is being applied to an article by effecting operation of the actuators associated with these valves, and a plurality of retaining means each of which is associated with one of said valves for preventing operation of the one valve to the closed condition at the end of the predetermined time period when suction is applied during the predetermined time period to a surface of an article at the fluid inlet associated with the one valve.
 6. A pick-up assembly as set forth in claim 5 wherein each of said actuators includes solenoid means for operating the associated one of said valves between the open and closed conditions and each of said retaining means includes a holding circuit means for preventing the associated solenoid means from being operated and a closing of the associated valve at the end of the predetermined time period when suction is applied to the surface of an article to be moved at the associated fluid inlet.
 7. A pick-up assembly as set forth in claim 6 further including a plurality of indicator means each of which is electrically connected with an associated holding circuit means and is operable to indicate when the associated one of said valves is in the open condition at the end of the predetermined period of time.
 8. A pick-up assembly as set forth in claim 5 wherein each of said retaining means includes an electrical switch which is electrically connected with the associated one of said actuators and is operable from a first condition to a second condition to prevent operation of the associated actuator and the associated one of sAid valves from the open condition to the closed condition at the end of the predetermined time period, each of said retaining means further including means for operating said electrical switch to the second condition in response to the application of suction to a surface of an article in the associated fluid inlet.
 9. A pick-up assembly as set forth in claim 8 further including display means for indicating which of said valves are in the open condition at the end of the predetermined time period and the spatial relationship between the fluid inlets associated with these valves.
 10. A pick-up assembly as set forth in claim 5 wherein each of said retaining means includes means for defining a chamber which is connected in fluid communication with the source of low pressure upon operation of the associated one of said valves to the open condition and means which is movable in response to a change in pressure to prevent operation of the associated one of said valves to the closed condition.
 11. A pick-up assembly as set forth in claim 5 further including a plurality of flexible cups each of which is mounted on said pick-up head in association with one of said fluid inlets and is operable to sealingly engage a surface of an article to be moved to facilitate the application of suction to the surface of the article.
 12. A pick-up assembly as set forth in claim 5 further including means for indicating which of said valves is in the open condition at the end of the predetermined time period.
 13. A pick-up assembly for use in moving articles, said pick-up assembly comprising a pick-up head having an array of fluid inlets, a plurality of passages each of which extends from an associated one of said fluid inlets to a source of low pressure, control means for controlling fluid flow through said passages so that only fluid inlets which are adjacent to the surface of an article to be moved are connected in fluid communication with the source of low pressure while the article is moved by the pick-up assembly, and indicator means for indicating which of the fluid inlets are connected to the source of low pressure as the article is moved by the pick-up assembly.
 14. A pick-up assembly as set forth in claim 13 wherein said indicator means includes display means for indicating the spatial relationship between the fluid inlets which are connected to the source of low pressure as the article is moved by the pick-up assembly.
 15. A pick-up assembly as set forth in claim 14 wherein said display means includes a plurality of lights which are arranged in an array similar to the array of fluid inlets, said indicator means further including a plurality of switches each associated with one of said fluid inlets, means for operating each of said switches from a first condition to a second condition when the associated one of said fluid inlets is connected to the source of low pressure as the article is moved by the pick-up assembly, and circuit means for electrically connecting each of said switches to an associated one of said lights.
 16. A pick-up assembly as set forth in claim 13 wherein said indicator means includes a plurality of switches each of which is associated with one of said fluid inlets and is operated from a first condition to a second condition upon application of suction to the surface of an article at the associated fluid inlet, said control means including a plurality of valves each of which is associated with one of said passages and is operable between a closed condition blocking fluid flow through the associated passage and an open condition, a plurality of electrical actuators each of which is associated with one of said valves for operating the associated valve to the open condition, and circuit means for activating said electrical actuators upon closing of the associated one of said switches.
 17. A pick-up assembly as set forth in claim 16 further including means associated with each of said switches for operating said switches in response to the Application of suction to the surface of an article at a fluid inlet associated with the switch.
 18. A pick-up assembly as set forth in claim 17 wherein said indicator means further includes display means for indicating the spatial relationship between the fluid inlets which are connected to the source of low pressure, said display means including a plurality of lights arranged in an array similar to the array of fluid inlets, said indicator means further including circuit means interconnecting said switches and said lights to effect energization of a light associated with one of said switches when the associated switch is in the second condition. 